#include <iostream>
#include <unistd.h>
#include <cstdlib>
#include <cstdio>
#include <string>
#include <sys/types.h>
#include <sys/wait.h>
#include <cstring>

#define N 2
#define NUM 1024

using namespace std;

void Writer(int wfd)
{

    string s = "hello I am child";
    pid_t self = getpid();
    int number = 0;
    char buffer[NUM];
    while(1)
    {
        //构建发送字符串
        buffer[0] = 0;
        snprintf(buffer, sizeof(buffer), "%s-%d-%d", s.c_str(), self, number++);
        //cout << buffer;
        
        //发送给父进程
        write(wfd, buffer, strlen(buffer));
        sleep(1);
        // sleep(1);        
        // char c = 'c';
        // write(wfd, &c, 1);
        // cout << number++ <<endl;
        // if(number >= 5) break;
    }
}
void Reader(int rfd)
{
    char buffer[NUM];
    int cnt = 5;
    while(cnt--)
    {
        buffer[0] = 0;
        ssize_t n = read(rfd, buffer, sizeof(buffer));
        if(n > 0)
        {
            buffer[n] = 0;
            cout << "father get a message : ["<<buffer << "]" << endl;   
        }
        //cout << "n :" << n << endl; 
        else if(n == 0)
        {
            cout << "father read file done ...." <<endl;
            break;
        }
        else break;

    }
}

int main()
{
    int pipefd[N] = {0};
    int n = pipe(pipefd);
    if(n < 0) return 1;
    // std::cout << "pipefd[0]: " << pipefd[0] << ", pipefd[1]: " << pipefd[1] << std::endl;
    
    pid_t id = fork();
    if(id < 0)
    {
        return 2;
    }
    else if(id == 0)
    {
        //child
        close(pipefd[0]);
    
        Writer(pipefd[1]);
    
        close(pipefd[1]);
        exit(0);
    }
    //father
    close(pipefd[1]);
    Reader(pipefd[0]);
    close(pipefd[0]);
    cout << "father close read fd" << pipefd[0] <<endl;
    sleep(5); // 为了维持一段时间的僵尸

    int status = 0; 
    pid_t rid = waitpid(id, &status, 0);
    if(rid < 0) return 3;
    cout << "wait child success: " << rid << "exit code: " << ((status>>8)&0xFF) << "exit signal: " << (status&0x7F) <<endl;
    
    sleep(5);
    cout << "father quit" <<endl;


    return 0;
}

